There are five Jantar Mantar monuments in India, of which the largest is in Jaipur which features many instruments along with the world’s largest stone sundial. The Vrihat Samrat yantra is a sundial that can give the local time to an accuracy of 2 seconds. It is a UNESCO World Heritage Site.
In the early 18th century, Maharaja Jai Singh II of Jaipur constructed five Jantar Mantars in total, in New Delhi, Jaipur, Ujjain, Mathura and Varanasi; they were completed between 1724 and 1735.